When a large-scale disaster occurs, for example, users of mobile stations may attempt use a mobile station and attempt voice telephony with relations such as family and friends in order to confirm each other's safety. At this point, if users access voice telephony all at once, the mobile communication network becomes congested, and establishing a telephony link becomes difficult.
Meanwhile, a telecommunication operator may implement a call restriction in order to reduce a congested state of concentrated access to specific links by mobile station users when an event, disaster, or the like occurs. For example, in a mobile communication system applying Wideband Code Division Multiple Access (W-CDMA) as the wireless access scheme, system information including a cell access restriction is broadcast to the mobile stations administered by a base station. A mobile station receiving system information restricts telephone calls in accordance with the cell access restriction included in the system information. For example, an access restriction of 50% yields a state in which a link establishing process is executed for only 50% of the ordinary accesses from users.
For details, see Japanese Laid-open Patent Publication No. 2011-249872 and International Publication Pamphlet No. WO 2008/126280.